The Repurposing Life

Grow an Avocado Tree from Seed

For the longest time I tried growing an avocado tree from a seed (pit) by using the suspending them over a glass of water with toothpicks method, and failed every time. The first try, I used only one seed, and when that failed (3 months later), I had to start all over from step 1. The second time, I used two seeds, just in case of failure, I’d have a backup. That attempt also failed. The third time, I used six seeds, only two of them made it to the planting in soil stage, and then failed. I read and re-read all the information online to figure out exactly what I was doing wrong, and then came across the method described below.

It is an easier way. It’ll show you a no-fuss way to root avocado pits to create new plants that you can grow indoors as houseplants. I recommend this method because it takes little effort and shows you exactly which seeds will germinate before planting them in pots.

Different Ways to Grow an Avocado Tree from Seed

Forget the toothpicks and water. And don’t bother with the plastic gizmo on Amazon that suspends the seed over water. This method works better. You will need a good potting mix but not much else. I have tested this easy method on a lot of grocery store avocados, and the germination rate is pretty good. I don’t like the toothpick method because it’s fussy, requires more effort, can rot the seed, and is not as reliable. You can also try sprouting avocado seeds directly in moist potting mix, but that too can be unreliable. I’d rather know the plant is going to succeed before going through the trouble of planting it.

Before You Start

A little reality check. Odds are, your avocado plant is not going to produce fruit, or, if it does, it will take many years and may not produce good fruit. Growing an avocado from seed is the slowest and least reliable way to get true (same as parent) fruit. Commercial growers use grafting methods to ensure fruit quality and quantity that are not really possible for home growers. But, starting a plant from the seed (pit) is an easy way to grow a free houseplant. If it does fruit, it could take as long as 8-20 years. Grafted avocados produce fruit in 2-3 years.

You can also use this same method for growing mango plants from seed from grocery store fruit.

Easy Method to Grow Avocado from Seed

It takes 4-6 weeks for avocado seeds to be rooted and ready for planting.

1. Remove the seed (pit) from a fresh, ripe avocado. Avoid using a knife so there is no damage to the seed.
2. Gently clean the seed under warm, running water using a soft brush or cloth ensuring all flesh is removed.
3. Wrap the seed in a sheet of damp (not dripping wet) paper towel or tea towel.
4. Place in a reusable silicone zip top or compostable food bag (do not zip shut) and store in a dark cupboard.
5. Check on it every 4 days or so. I put a reminder in my phone calendar so I don’t forget.
   • At first you just need to ensure the paper towel stays damp. After a few weeks you’ll start to notice signs of germination.
   • When the seed is germinating, it will gradually crack open, revealing a deep split, and, eventually a root (or roots) will grow from deep inside the seed.
   • Do not break the seed apart: the seed body feeds the root growth, and the roots are delicate, so handle with care and do not break them.
6. When the root is 3 inches long, your seed is ready for planting in soil.
7. If your root (or roots) are longer than 3 inches and they won’t fit in your pot, you can cut them back to 3 inches in length with sharp scissors cleaned with rubbing alcohol or a bleach solution (4 tsp. bleach per quart of water).

Related: Are Avocado Seeds Safe to Eat? No!

How to Plant a Sprouted Avocado Seed

Supplies

• 8 inch flower pot with drainage holes (for a 2 inch avocado seed)
• Indoor potting mix for houseplants

Avocados like good drainage so you can also amend the potting mix with perlite or sand if you like.

How to Tell Top From Bottom

Can you tell the top of your seed from the bottom? The top is usually tapered or pointy. The bottom is often broader and flat with a round, scaly marking. The roots will usually grow out from the bottom. Plant the sprouted seed with the bottom and roots aiming down into the pot.

Plant The Sprouted Seed

To plant, fill the pot half way with potting mix and gently place the seed in the pot. Handle with care so the roots do not break. While steadying the seed, gently press down the potting mix and add more as needed, leaving the top inch of the seed above soil level. The plant stem will grow from there. Water (distilled water) until moist, not wet. Top up the potting mix as needed. Place in warm, draft-free location with strong, but indirect light.

Caring for Your Avocado Plant

• Avocado (Persea): is a tropical plant
• Light: Full, indirect sun
• Humidity: Moderate to high
• Soil: do not dry out
• Fertilizer: 7-9-5
• Shape: Pinch back top leaves to encourage new side shoots
• Room Temperature: 60° to 85°F (16° to 30°C)

Propagation

• For Fruit: Start with a grafted tree
• For Fun: Grow seed into non-fruiting houseplant

Avocado Trivia

1. The word “avocado” originates from a word meaning “testicle.”
2. The fruit of an avocado tree is actually a large berry and the pit is a seed.
3. Avocados are considered a superfood, and a favored choice amongst us vegans, providing primarily monounsaturated fat, vitamins B₆, C, E, and potassium, magnesium, and folate.
4. Avocados are much richer in potassium than bananas: bananas have 358mg per 100 grams, avocados have 485mg per 100 grams.
5. The fruit must be left to mature on the tree, and then ripen after harvesting. The hard, green fruit can take two weeks to ripen, although this is faster if exposed to ethylene gas.
6. Grafted avocado plants produce fruit within a few years, compared to germinated seeds (8-20 years).
7. The pollination process for avocados is interesting: on day one female flowers open; on day two they become male and shed their pollen.
8. There are three species of avocados with many varieties. Fruit sizes and tastes vary.
   1. Guatemalan (Persea nubigena var. guatamalensis L. Wms.)
   1. Mexican (P. americana var. drymifolia Blake)
   1. West Indian (P. americana Mill. var. americana)
9. If you do not live in a growing area, the avocados in your grocery store probably come from the same few sources.

How to Grow an Avocado Tree Indoors

The first question most people ask is, can I grow avocados indoors? Plants: yes. Avocado fruit: depends. Unless you live in a tropical climate, your avocado houseplant is likely to just make for a nice, basic houseplant. Avocados grown from seed, also called the pit or stone, are slow growers and may not be mature enough to flower or fruit for 10-20 years if they do at all. And, if you’re really hoping for fruit (many years from now), keep in mind that the seeds are genetic combinations of two parents, so what the plant produces may not be the same as the fruit from which it originated.

If you get an avocado plant that is grafted-meaning a cutting from an avocado plant (the scion) is growing on compatible rootstock of another plant-you have a better chance of getting fruit. If growing conditions are right, a grafted plant could flower (or fruit) in 4-5 years. While it’s unlikely you will have the resources to graft an avocado plant at home, you can buy them already established. That said, it is fun to grow avocados from seed and nurture them as houseplants even if they never flower or fruit.

You can grow an avocado tree in your home as a houseplant, whether you started it from seed or a grafted plant. To propagate your own from a pit, these step-by-step instructions will guide you, How to Grow Avocado from Seed.

1. Overview

It’s always helpful to know the natural history of a plant to get a good understanding of the best growing conditions. The more we can replicate them at home, the better they will thrive.

• Avocadoes (Persea spp.) are tropical plants hardy in zones 9 to 11, and belong to the Lauraceae family (cinnamon, bay laurel).
• The fruit of the avocado, also called pears, are actually single seed berries that ripen after harvesting.
• Like many houseplants, avocado plants can be toxic to animals including cats and dogs.
• Avocado trees grown indoors are not reliable fruit producers but make nice, basic houseplants.
• Avocado trees grown outdoors, in tropical zones, can live to be 50, 100, and sometimes hundreds of years old.

Read more interesting avocado trivia here.

2. Potting Soil & Containers

• Avocados like well-drained soil: use general indoor potting mix designed for houseplants.
• Use a container with drainage holes and a deep saucer to catch excess water.
• Avocados have shallow root systems, so no need for a extra deep container.
• The pot should be a few inches wider in diameter than the roots of the plant.

3. Light

• Full, indirect sun

Avocados originated as trees growing in the understory of tropical forests (plant zones 9 to 11). This means they love the warmth and humidity with the protection of overhead shade provided by the taller trees. To replicate this environment indoors, provide full sun but not directly at the window. Instead, set the plant back a foot or so.

4. Indoor Temperatures

• Provide consistent temperatures in the range of 16° to 30°C (60° to 85°F).

No need to change your indoor temperature just to suit a plant, but your avocado tree will like it best if the temperatures remain steady with humidity around 50%. If you move an avocado into a drastically different growing environment, it may drop its leaves, and struggle or die. It’s the change that affects them.

Dropping Leaves or Leaves Turning Brown?

This is common with seasonal changes indoors. Change of light and humidity can make the plant sulk: leaves may turn brown and drop. Unless you can maintain constant conditions indoors with grow lights and a humidifier keeping it around 50%, leaf drop will happen. Don’t give up: the plants will rebound when winter is done and the central heating is off once again.

5. Water

• Keep soil moderately moist, do not allow it to dry out.

Just as avocados don’t like drastic light or temperature changes, they need consistent watering with tepid water. When it is time to water:

• Give the soil a complete soaking.
• Let the excess water drain to a dish below.
• Pour away the excess after 30 minutes.

I use a moisture meter to check the soil, and water again frequently. You can also use your finger tip to check how moist the soil is. Just push your finger tip into the potting mix and if it’s dry or near dry, it’s time to water. The occasional spray mist of water on the leaves is also recommended, especially if your indoor humidity levels are lower as they tend to be in winter. If you have hard water, use boiled and cooled, or distilled.

Water Problems

• Signs of under watering: brown edges and leaf drop
• Signs of over watering: curled leaves and soft stems

6. Fertilizing

• Use a balanced houseplant fertilizer (7-9-5) according to instructions on label.

Once leaves have formed, you can add a balanced houseplant fertilizer every 3 months, following directions on product label. My preference is to use a fraction of the recommended dose on an ongoing basis from late winter to late fall. Or, use a slow-release fertilizer on the surface of the soil.

7. Pruning

Without some pruning, avocados grown from seed tend to grow one, single stem that will grow very tall. Once you have several leaves on the stem, you can pinch back the top ones to encourage side growth. You may have to do this several times, waiting for the main stem to thicken before allowing the plant to grow taller, otherwise it will buckle under the weight of its leaves.

8. Repotting

As the plant grows, the roots will need more room and you will need to repot it into the next size up container. By the time the plant fits a 24 inch wide pot, it could be ready to start fruiting.

9. Flowering

The sexual reproduction of avocados is very interesting. Avocado plants are self-fertile with two main types:

• One produces male flowers in the morning, and female in the afternoon. The other does the same, but in reverse.
• Pollination can occur when the two flowers overlap.
• Professional growers have many trees of both types to ensure pollination.

It is unlikely your indoor, homegrown avocado tree will flower or fruit—unless you live in a tropical climate.

10. Outdoors

Like many houseplants, you can transfer your avocado tree outdoors during the summer months. The goal is to provide similar growing conditions to those indoors:

• Indirect sun
• Moderate humidity
• Soil that is always moist

There’s always a risk of bringing pests into your house when the plants are brought back indoors, so take precautions by inspecting the plant and removing any insects, slugs, or aphids to avoid problems.

11. Summary

• Full, indirect sun.
• Moderate to high humidity
• Never allow soil to dry out
• Pinch off top leaves if plant becomes “leggy”
• Mist with water occasionally
• Use a 7-9-5 houseplant fertilizer as directed

More Info on Growing Avocados

• Avocado Information, University of California Agriculture & Natural Resources

Sources:
How to Grow an Avocado from Seed (Easy Method)
https://empressofdirt.net/grow-avocado-seed-easy/
January 7, 2019 by Melissa J. Will
How to Grow an Avocado Tree
https://empressofdirt.net/grow-avocado-tree/
January 18, 2021 by Melissa J. Will